#118 RMI Motorsport (RDLMS)Premium

The BTB tracks are stored in a folder in the root RBR directory (RBR root\BTBRS).

I think you can just delete them from there without issue. I think the RSCenter client checks if you have the BTB files at runtime, rather than maintain a list of BTB tracks installed. I'd back them up first, delete the originals, try the game, if it works, then delete the backups, else copy them back.